Small jacking force weighing structure and method for rotation method construction of cross-railway continuous beam bridge

Abstract

The invention discloses a small jacking force weighing structure for rotation method construction of a railway-crossing continuous beam bridge. A rotation spherical hinge is arranged between an upper bearing platform and a lower bearing platform of a continuous beam bridge system; the weighing structure comprises a weighing support system arranged below the end part of the concrete box girder; and a weighing system. And a pier beam consolidation system is arranged between the continuous beam bridge system and the concrete box beam. The structure is located at the end of the concrete box girder, the moment of force at the fulcrum of the main pier is large, the jacking force needed when the rigid body is in a rotation critical state is small, the displacement is easy to read, the weighing test is safer than a conventional method, the technology is advanced, the test efficiency is high, the cost is greatly reduced, and the engineering quality is easy to guarantee. When a continuous beam bridge, a rigid frame bridge and a cable-stayed bridge which are more than twenty thousand tons are constructed by adopting a swivel method, the weighing test advantages are obvious, the weighing test method for building a highway and municipal large-span flat turn bridge is enriched, and the method has a great popularization value.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a small-scale jacking structure and method for constructing a continuous beam bridge across a railway using the rotation method. Background Technology

[0002] When constructing highway and municipal bridges that cross operating railway lines, the short construction window prevents prolonged construction above the railway. Therefore, a lower rotation method is typically used. First, the piers and abutments are constructed on sites parallel to the operating railway line, and concrete box girders are poured. Then, traction steel cables pull an upper turntable, rotating the piers and concrete box girders horizontally to the designed bridge location. Previously, before the rotation, jacking and weighing were performed on the lower abutment. However, the piers and girders are heavy, requiring enormous jacking force, and the displacement is not significant, posing a risk of overturning during the weighing test.

[0003] Therefore, based on the above-mentioned technical problems, those skilled in the art urgently need to develop a small-force weighing structure and method for the construction of continuous beam bridges across railways using the rotation method. Summary of the Invention

[0004] The purpose of this invention is to provide a small-force weighing structure and method for the construction of continuous beam bridges across railways using the rotation method. This weighing structure is located at the end of the concrete box girder, with a large torque at the main pier. The required jacking force when the steel body is in the critical rotation state is small, the displacement is easy to read, the weighing test is safer than conventional methods, the technology is advanced, the test efficiency is high, and the cost is greatly reduced. Moreover, the engineering quality is easy to ensure. The weighing test has obvious advantages when using the rotation method for continuous beam bridges, rigid frame bridges, and cable-stayed bridges with a capacity of 10,000 tons or more. It enriches the weighing test methods for the construction of long-span horizontal rotation bridges in highways and municipal engineering, and has great promotional value.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: The present invention discloses a small-scale jacking weighing structure for the construction of a continuous beam bridge across a railway using the rotation method. The weighing structure is located at the end of a concrete box girder, and the middle part of the concrete box girder is supported by hollow bridge piers. A spherical hinge is provided between the upper and lower abutments of the continuous beam bridge system. The weighing structure includes: A weighing support system arranged below the ends of the concrete box girder; and A weighing system is installed between the weighing support system and the concrete box girder; A pier-beam consolidation system is provided between the hollow pier and the concrete box girder.

[0006] Furthermore, the continuous beam bridge system includes: The lower foundation is poured into the bottom; After the lower bearing platform is poured, the rotating ball joint is installed on the lower bearing platform, and the upper bearing platform is above the rotating ball joint; Hollow piers are constructed on the top of the upper pier, and rubber bearings are installed between the top of the hollow piers and the concrete box girder. The hollow piers are connected to the poured concrete box girder by prestressed steel bars.

[0007] Furthermore, a temporary consolidation structure is provided between the upper support platform and the lower support platform; The upper bearing platform template is installed above the rotating ball hinge. The rotating traction steel strands and embedded parts are pre-embedded in the steel reinforcement skeleton of the upper bearing platform. After the steel strands are fixed by the anchor, the upper bearing platform concrete is poured.

[0008] Furthermore, the pier-beam consolidation system includes: Prestressed steel bars embedded in the solid section at the top of the hollow bridge pier; The front and rear templates of the rubber bearing are installed, and four sets of concrete support pads are poured. The prestressed steel bars pass through the concrete support pads and the concrete box girder. Anchor nuts are installed on the portion of the prestressed steel bars that extend to the upper end of the concrete box girder.

[0009] Furthermore, the weighing support system includes: The concrete foundation at the bottom; An embedded steel plate is installed at the upper end of the concrete foundation; Three steel pipe columns are welded and fixed to the upper end of the pre-embedded steel plate, and the three steel pipe columns are connected by a horizontal connecting beam. The upper end of the steel pipe column is fixed to a steel platform, and the weighing system is set between the steel platform and the concrete box girder.

[0010] Furthermore, the weighing system includes: A lifting jack is installed at the upper end of the weighing support system via a steel support beam. A dial indicator located inside the lifting jack, with its measuring rod resting against the bottom of the concrete box girder; The weighing system also includes a data acquisition unit, a pressure sensor, a displacement sensor, and a PLC control console; The displacement sensor and the data acquisition unit, as well as the pressure sensor and the data acquisition unit, are all connected via data cables, and the data acquisition unit, pressure sensor, and displacement sensor are all connected to the PLC control console via data cables.

[0011] Furthermore, a counterweight system is provided on the upper part of the concrete box girder; The counterweight system is a counterweight water tank, and the counterweight water tank is connected by steel profile connectors.

[0012] Furthermore, the load-bearing support system is located 0.7m from the end of the concrete box girder.

[0013] This invention discloses a small-force weighing method for the construction of a continuous beam bridge across a railway using the rotation method. The method is characterized by being based on the small-force weighing structure for the construction of a continuous beam bridge across a railway using the rotation method described above.

[0014] Furthermore, the weighing structure is used to test rigid body displacement abrupt changes, and the weighing is divided into the following forms: The first form is: When the frictional torque M provided by the rotating ball joint Z Greater than the unbalanced torque M of the rotating body G At this point, the unbalanced torque of the rotating body is canceled out by the frictional torque generated by the ball joint, and the beam maintains a balanced state, without any rigid body displacement around the ball joint. The support legs are not on the ground at this time, and jacking forces are applied to both sides of the rotating body in the longitudinal or transverse direction. During the jacking process, the rotating body undergoes slight counterclockwise and clockwise rotations in the vertical plane along the beam axis. By plotting the jacking force-displacement curve, the critical point and critical jacking forces P1 and P2 are identified. A system of simultaneous equations is established based on the torque balance principle to solve for the frictional torque M of the ball joint. Z and the unbalanced torque M of the rotating body itself G ; M G = (P1L1-P2L2) / 2; M Z = (P1L1 + P2L2) / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P2: Lifting force at the critical state of slight rotation at the second end of the concrete box girder; L1: Lever arm of the lifting force at the first end of the concrete box girder; L2: Lever arm of the lifting force at the second end of the concrete box girder; The second form is: When the frictional torque M provided by the rotating ball joint Z Less than the unbalanced torque M of the rotating body itself GAt this point, the frictional resistance generated by the rotating ball joint is insufficient to resist the unbalanced moment of the rotating body itself. After the beam undergoes rigid body displacement, the support legs participate in the work. The resisting moment generated by the support legs and the frictional resistance moment of the rotating ball joint jointly resist the unbalanced moment of the rotating body, maintaining the stability of the system. At this time, the support legs touch the ground, and a jacking force is applied on the side where the support legs touch the ground. Record the jacking force, starting from the moment the support legs leave the ground, gradually increasing to the moment when the ball joint rotates slightly, P1. Then lower the jack, and let P1' be the jacking force when the ball joint rotates slightly during the gradual lowering of the jack. During the lifting and lowering process, by plotting the jacking force-displacement curve, find the critical point and the critical lifting forces P1 and P1'. Establish a system of simultaneous equations based on the principle of moment balance to solve for the frictional torque M of the rotating ball joint. Z and the unbalanced torque M of the rotating body itself G ; M G =(P1+P1')L1 / 2; M Z = (P1-P1')L1 / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P1': Lifting force at the critical state of slight rotation during the fall of the first end of the concrete box girder; L1: Lever arm of the lifting force at the first end of the concrete box girder; Furthermore, the eccentricity of the two types of rotating bodies is: e = M G / G; The static friction coefficient of the rotating ball joint is: µ =M Z / (RG; In the formula: M G —The unbalanced torque of the rotating body itself; M Z —Spherical hinge friction torque; R—radius of the ball joint; G—Total weight of the rotating body.

[0015] In the above technical solution, the present invention provides a small-load-bearing structure for the construction of a continuous beam bridge across a railway using the rotation method, which has the following beneficial effects: The weighing structure and method of this invention are located at the end of the concrete box girder, with a large torque at the main pier pointing point, requiring less jacking force when the steel body is in the critical rotation state, and the displacement is easy to read. The weighing test is safer than conventional methods, with advanced technology, high test efficiency, and significantly reduced costs. Moreover, the engineering quality is easy to ensure. The weighing test has obvious advantages when using the rotation method for continuous beam bridges, rigid frame bridges, and cable-stayed bridges with a capacity of 10,000 tons or more. It enriches the weighing test methods for the construction of long-span horizontal rotation bridges in highways and municipal engineering, and has great promotional value. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of a small-scale jacking structure for the construction of a continuous beam bridge across a railway using the rotation method, as disclosed in an embodiment of the present invention. Figure 2 This invention discloses a weighing test setup for a small-scale jacking weighing structure constructed using the rotation method for continuous beam bridges spanning railways, where the support legs are not on the ground. Figure 1 ; Figure 3 This invention discloses a weighing test setup for a small-scale jacking weighing structure constructed using the rotation method for continuous beam bridges spanning railways, where the support legs are not on the ground. Figure 2 ; Figure 4 This invention discloses a method for weighing a continuous beam bridge across a railway using the rotation method with a small jacking force weighing structure, where the support legs are in contact with the ground. Figure 1 ; Figure 5 This invention discloses a method for weighing a continuous beam bridge across a railway using the rotation method with a small jacking force weighing structure, where the support legs are in contact with the ground. Figure 2 ; Figure 6 This is a structural schematic diagram of a counterweight scheme for a small-scale jacking weighing structure used in the rotation method for constructing a continuous beam bridge across a railway, as disclosed in an embodiment of the present invention. Figure 7 This is a plan view of a pier-beam consolidation system for a small-force-weighing structure constructed using the rotation method for a continuous beam bridge across a railway, as disclosed in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Continuous beam bridge system; 2. Pier-beam integration system; 3. Weighing system; 4. Weighing support system; 5. Counterweight system; 11. Concrete box girder; 12. Rubber bearing; 13. Hollow pier; 14. Upper pier cap; 15. Lower pier cap; 16. Rotating ball hinge; 21. Concrete support pad; 22. Prestressed steel reinforcement; 23. Anchor nuts; 31. Lifting jack; 32. Dial indicator; 33. Data acquisition unit; 36. PLC control console; 41. Concrete foundation; 42. Embedded steel plate; 43. Steel pipe column; 44. Horizontal connecting beam; 45. Steel platform; 51. Counterweight water tank. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0020] See Figures 1 to 7 As shown; This embodiment describes a small-scale jacking weighing structure for the construction of a continuous beam bridge across a railway using the rotation method. The weighing structure is located at the end of a concrete box girder 11, with the middle section of the concrete box girder 11 supported by hollow piers 13. A spherical hinge 16 is provided between the upper abutment 14 and the lower abutment 15 of the continuous beam bridge system 1; The weighing structure includes: A weighing support system 4 is arranged below the ends of the concrete box girder 11; and The weighing system 3 is installed between the weighing support system 4 and the concrete box girder 11; A pier-beam consolidation system 2 is installed between the hollow pier 13 and the concrete box girder 11.

[0021] Specifically, the load-bearing structure disclosed in this embodiment is applicable to the construction of highway and municipal bridges crossing railways using the unbalanced horizontal rotation method. When the pier height is no more than 25m, the lower rotation method is usually adopted. First, the pier caps and piers are constructed on both sides of the operating railway line. At the same time, steel rotating ball joints 16 are constructed on the lower pier cap 14 and the upper pier cap 15. Then, the upper concrete box girder 11 is poured in the direction parallel to the railway line. Finally, the turntable is pulled by traction steel bundles to rotate the entire pier and girder horizontally to the designed bridge position. However, during the pouring of the concrete box girder 11, a weight difference between the two ends is inevitable, resulting in an unbalanced moment on the main pier. Therefore, the box girder needs to be weighed and counterweighted before rotation to make the center of gravity of the rotating system coincide with the center of gravity of the ball joint rotation axis. A lifting jack 31 is installed at the end of the upper concrete box girder 11. The torque at the main pier is large, and the jacking force required when the rigid body is in the critical state of rotation is small. The weighing test is safer than the conventional method. It highlights the advanced technology and high efficiency in the rotation construction of 20,000 tons and above, and improves the testing operation environment and saves social resources such as large jacks. The benefits are significant and the results are good.

[0022] Preferably, the continuous beam bridge system 1 in this embodiment includes: The lower support 15 is poured into the bottom. After the lower bearing platform 15 is poured, a rotating ball joint 16 is installed on the lower bearing platform 15, and the upper bearing platform 14 is above the rotating ball joint 16. Hollow piers 13 are constructed on the top of the upper abutment 14. Rubber bearings 12 are installed between the top of the hollow piers 13 and the concrete box girder 11. The hollow piers 13 are connected to the poured concrete box girder 11 by prestressed steel bars 22.

[0023] In this embodiment, a temporary consolidation structure is provided between the upper support 14 and the lower support 15; The upper bearing platform template is installed above the spherical hinge 16. The spherical hinge traction steel strands and embedded parts are pre-embedded in the steel reinforcement cage of the upper bearing platform. After the steel strands are fixed by the anchor, the upper bearing platform concrete is poured.

[0024] After the lower abutment 15 of the continuous beam bridge system 1 in this embodiment is poured, a rotating ball hinge 16 is installed. This rotating ball hinge 16 needs to bear a load of not less than 23,700 tons. The upper abutment formwork is installed above the rotating ball hinge 16. The upper abutment 14 includes a circular turntable with a diameter of 9.9m. The rotating rigid foot line traction bundle and related embedded parts are pre-embedded in the turntable steel reinforcement cage. The steel bundle is fixed with anchors. Then, the upper abutment concrete is poured, and the upper and lower abutments are temporarily fixed with pre-embedded I-beams to prevent rotation. Hollow piers 13 are constructed on top of the upper abutment 14. Structural rubber bearings 12 are installed on top of the piers. Then, a disc-type full-span scaffold is erected parallel to the railway line. The upper concrete box girder 11 is poured on site, which must use large segments of 12m to 16m.

[0025] Preferably, the pier-beam consolidation system 2 in this embodiment includes: Prestressed steel bars 22 are embedded in the solid section at the top of the hollow pier 13; The front and rear templates of the rubber bearing 12 are installed, and four sets of concrete support pads 21 are poured. The prestressed steel bars 22 pass through the concrete support pads 21 and the concrete box girder 11. Anchor nuts 23 are installed on the portion of the prestressed steel bar 22 that extends to the upper end of the concrete box girder 11.

[0026] In this embodiment, after the pre-embedded stress steel bars 22 in the solid section at the top of the hollow pier 13 in the pier-beam consolidation system 2, the pier concrete is poured. Subsequently, templates are installed before and after the rubber bearings at the top of the pier, and a total of 6 concrete support blocks 21 are poured, 3 at the front and 3 at the back. The support blocks are 4.5m*0.75m in size and 1.1m in height. C50 concrete is poured, and the prestressed steel bars are poured into the concrete support blocks 21 and the 0# block of the box girder. The prestressed steel bars 22 are 6 sets of 9-16mm unbonded prestressed steel bars, with 1 set in each support block 21. After the 0# block of the box girder reaches the design strength, the prestressed steel bars 22 are tensioned on the top of the 0# block. After tensioning, UPSb16-3 anchor nuts 23 are used to lock them, forming the pier-beam temporary consolidation system 2 of this embodiment.

[0027] Preferably, the weighing support system 4 of this embodiment includes: a concrete foundation 41 at the bottom and an embedded steel plate 42 set on the upper end of the concrete foundation 41; in this embodiment, three steel pipe columns 43 are welded and fixed to the upper end of the embedded steel plate 42, and the three steel pipe columns 43 are connected by a horizontal connecting beam 44. The upper end of the steel pipe column 43 is fixed to the steel platform 45, and the weighing system 3 is set between the steel platform 45 and the concrete box girder 11.

[0028] The weighing system 3 includes: Lifting jacks 31 are installed on the upper end of the weighing support system 4 via steel beams; The dial indicator 32 is located inside the lifting jack 31, and the measuring rod of the dial indicator 32 is pressed against the bottom of the concrete box girder 11. The weighing system 3 also includes a data acquisition unit 33, a pressure sensor, a displacement sensor, and a PLC control console 36; The displacement sensor and the data acquisition unit 33, as well as the pressure sensor and the data acquisition unit 33, are connected by data cables. The data acquisition unit 33, the pressure sensor, and the displacement sensor are all connected to the PLC control console 36 via data cables.

[0029] This embodiment further defines a weighing system 3 and a load-bearing support system 4; wherein, the weighing system 3 includes lifting jacks 31, dial indicators 32, data acquisition devices 33, pressure sensors, displacement sensors, and a PLC control console 36. Before removing the temporary sand box, displacement sensors, pressure sensors, data acquisition devices 33, and the PLC control console 36 are arranged on the weighing bracket at the end of the box girder. The installation position of the jacks is accurately measured, the support height is checked, and steel support beams are installed. Six lifting jacks 31 are installed on the support beams. After installation, it is ensured that the jacks are installed horizontally and that the support and support beams are securely connected. A dial indicator 32 is installed inside the jack installation position, with the dial indicator 32 probe against the bottom of the box girder, and the initial reading is taken. The displacement sensors and data acquisition devices 33, and the pressure sensors and data acquisition devices 33 are connected via data cables, and then connected to the PLC control console 36.

[0030] Secondly, the load-bearing support system 4 in this embodiment includes a concrete foundation 41, an embedded steel plate 42, steel pipe columns 43, a horizontal connecting beam 44, and a steel platform 45. A C30 concrete foundation 41 is poured on the ground below the end of the box girder. A δ20mm embedded steel plate is installed on top of the concrete foundation 41. Three steel pipe columns 43, approximately 6.5m high, are erected on top of the concrete foundation 41. The steel pipe columns 43 are made of Ф299×7.5mm steel pipes, with their bottoms welded to the steel plate. A Ф51×3.5mm horizontal connecting beam 44 connects the steel pipe columns 43 at half their height. A steel platform 45 is installed on top of the steel pipe columns 43. The steel platform 45 is assembled from [20-type steel, with a 10mm thick steel plate on top, used to house the lifting jack 31, displacement gauge, and for weighing test operations.

[0031] Preferably, in this embodiment, a counterweight system 5 is provided on the upper part of the concrete box girder 11; the counterweight system 5 is a counterweight water tank 51, and the counterweight water tank 51 is connected by a steel connector.

[0032] In this embodiment, the counterweight water tank 51 is made of δ20mm steel plate. Based on the calculation of the unbalanced torque, the appropriate counterweight F and position are determined, and the lever arm distance L is accurately measured using a steel ruler. The water tank is welded to the top of the box beam using steel connectors, ensuring that the center of gravity of the water tank coincides with the determined counterweight position.

[0033] Preferably, in this embodiment, the load-bearing support system 4 is arranged at a position 0.7m from the end of the concrete box girder 11.

[0034] In this embodiment, arc length and angle observation scales are set on the circular turntable of the upper bearing platform to facilitate observation and verification during the rotation process and control the horizontal rotation position of the beam. Secondly, after the concrete box girder is rotated into place, a comprehensive measurement of the rotating beam is performed, first the axis, then the elevation, to adjust the beam's posture. The axis adjustment uses a point-operated traction jack, applying or releasing jacking force on the weighing support frame, which facilitates the adjustment of the beam's elevation. Finally, after the concrete box girder's posture adjustment meets the design requirements, wedge-shaped steel plates are used to secure the support feet and lock the upper turntable. Immediately afterward, the hinge-sealing concrete is poured. Once the hinge-sealing concrete reaches 80% of its design strength, the closure section construction is carried out as soon as possible.

[0035] This invention discloses a small-force weighing method for the construction of a continuous beam bridge across a railway using the rotation method. The method is characterized by being based on the small-force weighing structure for the construction of a continuous beam bridge across a railway using the rotation method described above.

[0036] Preferably, the weighing structure in this embodiment is used to test the sudden displacement of a rigid body, and the weighing is divided into the following forms: The first form is: When the frictional torque M provided by the rotating ball joint 16 Z Greater than the unbalanced torque M of the rotating body GAt this point, the unbalanced torque of the rotating body is canceled out by the frictional torque generated by the ball joint, and the beam maintains a balanced state, without producing rigid body displacement around the ball joint 16. The support legs are not on the ground at this time, and jacking forces are applied to both sides of the rotating body in the longitudinal or transverse direction. During the jacking process, the rotating body undergoes slight counterclockwise and clockwise rotations in the vertical plane along the beam axis. By plotting the jacking force-displacement curve, the critical point and critical jacking forces P1 and P2 are identified. A system of simultaneous equations is established based on the torque balance principle to solve for the frictional torque M of the ball joint. Z and the unbalanced torque M of the rotating body itself G ; M G = (P1L1-P2L2) / 2; M Z = (P1L1 + P2L2) / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P2: Lifting force at the critical state of slight rotation at the second end of the concrete box girder; L1: Lever arm of the lifting force at the first end of the concrete box girder; L2: Lever arm of the lifting force at the second end of the concrete box girder; The second form is: When the frictional torque M provided by the rotating ball joint 16 Z Less than the unbalanced torque M of the rotating body itself G At this point, the frictional resistance generated by the rotating ball joint 16 is insufficient to resist the unbalanced moment of the rotating body itself. After the beam undergoes rigid body displacement, the support legs participate in the work. The resisting moment generated by the support legs and the frictional resistance moment of the rotating ball joint 16 jointly resist the unbalanced moment of the rotating body, maintaining the stability of the system. At this time, the support legs are on the ground, and a jacking force is applied on the side where the support legs are on the ground. Record the jacking force, which gradually increases from the moment the support legs leave the ground to the moment when the ball joint rotates slightly. Then lower the jack. Let P1' be the jacking force when the ball joint rotates slightly during the gradual lowering of the jack. During the lifting and lowering process, by plotting the jacking force-displacement curve, find the critical point and the critical lifting forces P1 and P1'. Establish a system of simultaneous equations based on the principle of moment balance to solve for the frictional torque M of the rotating ball joint. Z and the unbalanced torque M of the rotating body itself G ; M G =(P1+P1')L1 / 2; M Z = (P1-P1')L1 / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P1': Lifting force at the critical state of slight rotation during the fall of the first end of the concrete box girder; L1: Lever arm of the lifting force at the first end of the concrete box girder; Furthermore, the eccentricity of the two types of rotating bodies is as follows: e=M G / G; The static friction coefficient of the rotating ball joint is: µ =M Z / (RG; In the formula: M G —The unbalanced torque of the rotating body itself; M Z —Spherical hinge friction torque; R—radius of the ball joint; G—Total weight of the rotating body.

[0037] The weighing method uses lifting jacks and a displacement sensing system installed on the support frame. It requires little jacking force, is sensitive to beam displacement, and ensures safe weighing tests. The construction steps are as follows: 1. Determine the form of abrupt changes in rigid body displacement Before weighing, clean the support legs and slideways, gradually and symmetrically remove the wedges at the sand box and support legs, temporarily release the temporary fastening between the upper and lower bearing platforms, and complete the conversion of the entire rotating system support system. Observe whether the support legs are on the ground (continuous measurement is carried out to observe whether the support legs continue to sink to one side as the sand box is removed). If the support legs are not on the ground, jacking force needs to be applied to both sides of the rotating body in the longitudinal direction. If the support legs are on the ground, jacking force is only applied to the side on the ground.

[0038] 2. Install jacks and dial indicators Before removing the temporary support sand box, place displacement sensors and read initial readings. Accurately measure the jack installation positions; they should be symmetrically arranged at both ends below the turntable on the bridge's longitudinal axis. Verify the support height, install steel support beams, and then install the lifting jacks on the support beams. After installation, ensure the jacks are level and the supports or support beams are stable. To meet the synchronous lifting requirements, six OVM-150-ton jacks are used uniformly. To ensure even stress distribution on the beam during lifting, 300×300×20mm steel plates are placed on top of the jacks.

[0039] 3. Test top Adjust the jacks to bring all lifting jacks 31 to the set initial jacking pressure state, and record the readings of the pressure sensor and displacement sensor.

[0040] Before the formal jacking, a trial jacking should be conducted, using a jacking force of 100t. The trial jacking is mainly to eliminate the inelastic deformation or settlement of the jack support frame itself. It can be stopped before the main beam is formally jacked up, and the frame should be left for two hours for observation. Only after no changes are observed can the overall jacking begin.

[0041] 4. Lifting and Recording Each weighing support frame has three jacks connected to a set of oil pumps, controlled by a PLC system to maintain consistent lifting force; each jack is managed by a designated person who monitors the readings at all times. Lifting is directed by a designated person who issues commands uniformly.

[0042] The jacking force is applied in multiple stages, initially at 20%–40%–60%. Once 60% force is applied, the force is increased by 5% in each stage, causing minute changes in the displacement gauge, and the displacement is recorded simultaneously until a sudden change in the displacement of the rotating body occurs. During jacking, both vertical displacement and jack pressure gauge readings are used for dual control, recording the displacement and jacking force at each stage. The error between the pressure gauge readings and theoretical calculations during jacking should not exceed ±1.0 MPa.

[0043] Following the rigid body displacement mutation pattern determined in step 1, repeat the above test on another weighing support frame.

[0044] 5. Plot the F-Δ curve Based on the jacking force and displacement records, plot the F-Δ curve (jacking force - displacement) of the jacking process. Then, using the rigid body displacement mutation form, substituting the appropriate formula, calculate the ball joint friction torque M. Z and the unbalanced torque M of the rotating body itself G .

[0045] 6. Calculate the test results (1) Support foot not touching the ground M G =(P1L1-P2L2) / 2; M Z =(P1L1+P2L2) / 2 (2) Support foot already on the ground M G =(P1+P1')L1 / 2; M Z =(P1-P1')L1 / 2 (3) Eccentricity of the rotating body in the above two forms: e=M G / G, Static friction coefficient of ball joint: µ=M Z / (RG; 7. Determine the counterweight scheme In this embodiment, the rotation construction adopts an absolute balance counterweight scheme for the beam. The counterweight ensures that the center of gravity of the rotating body of the pier-beam passes through the vertical axis of the ball joint, thus maintaining the balance of the rotating body under static conditions. After the counterweight is applied, the weight deviation of the cantilever on both sides of the continuous box girder "T" does not exceed ±2%. The counterweight is calculated according to the following formula: Where: F—counterweight (kN); L—Distance (m) from the counterweight water tank to the vertical axis of the ball joint.

[0046] The specific counterweight scheme is determined by considering two factors: the weight F that the water tank can counterweight on site and the location where the water tank is placed that will not affect construction.

[0047] In the above technical solution, the present invention provides a small-load-bearing structure for the construction of a continuous beam bridge across a railway using the rotation method, which has the following beneficial effects: The weighing structure and method of this invention are located at the end of the concrete box girder, with a large torque at the main pier pointing point, requiring less jacking force when the steel body is in the critical rotation state, and the displacement is easy to read. The weighing test is safer than conventional methods, with advanced technology, high test efficiency, and significantly reduced costs. Moreover, the engineering quality is easy to ensure. The weighing test has obvious advantages when using the rotation method for continuous beam bridges, rigid frame bridges, and cable-stayed bridges with a capacity of 10,000 tons or more. It enriches the weighing test methods for the construction of long-span horizontal rotation bridges in highways and municipal engineering, and has great promotional value.

[0048] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A small-load-bearing structure for the rotation method of a continuous beam bridge across a railway, characterized in that, The weighing structure is located at the end of the concrete box girder (11), and the middle part of the concrete box girder (11) is supported by a hollow pier (13). A spherical hinge (16) is provided between the upper abutment (14) and the lower abutment (15) of the continuous beam bridge system (1). The weighing structure includes: A weighing support system (4) arranged below the ends of the concrete box girder (11); and The weighing system (3) is located between the weighing support system (2) and the end of the concrete box girder (11). A pier-beam consolidation system (2) is provided between the hollow pier (13) and the concrete box girder (11).

2. The small-jacking-force-weighing structure for the construction of a continuous beam bridge across a railway using the rotation method according to claim 1, characterized in that, The continuous beam bridge system (1) includes: The lower support (15) is poured into the bottom. After the lower bearing platform (15) is cast, the rotating ball joint (16) is installed on the lower bearing platform (15), and the upper bearing platform (14) is above the rotating ball joint (16). Hollow piers (13) are constructed on the top of the upper abutment (14). Rubber supports (12) are installed between the top of the hollow piers (13) and the concrete box girder (11). The hollow piers (13) are temporarily fixed to the poured concrete box girder (11) by prestressed steel bars (22).

3. The small-load-bearing structure for the rotation method of a continuous beam bridge across a railway as described in claim 2, characterized in that, A temporary consolidation structure is provided between the upper support platform (14) and the lower support platform (15); The upper bearing plate template is installed above the rotating ball joint (16). The rotating traction steel strand and embedded parts are pre-embedded in the steel reinforcement skeleton of the upper bearing plate. After the steel strand is fixed by the anchor, the upper bearing plate concrete is poured.

4. The small-jacking-force-supported structure for the construction of a continuous beam bridge across a railway using the rotation method according to claim 2, characterized in that, The pier-beam consolidation system (2) includes: Prestressed steel bars (22) are embedded in the solid section at the top of the hollow pier (13). The rubber bearing (12) is installed with front and rear templates, and four sets of concrete support pads (21) are poured. The prestressed steel bars (22) pass through the concrete support pads (21) and the concrete box girder (11). Anchor nuts (23) are installed on the portion of the prestressed steel bar (22) that extends to the upper end of the concrete box girder (11).

5. A small-load-bearing structure for the construction of a continuous beam bridge across a railway using the rotation method, as described in claim 1, is characterized in that... The weighing support system (4) includes: The bottom concrete foundation (41); An embedded steel plate (42) is set on the upper end of the concrete foundation (41). The upper end of the pre-embedded steel plate (42) is welded and fixed with three steel pipe columns (43), and the three steel pipe columns (43) are connected by a horizontal connecting beam (44). The upper end of the steel pipe column (43) is fixed to the steel platform (45), and the weighing system (3) is located between the steel platform (45) and the end of the concrete box girder (11).

6. A small-jacking-force-weighing structure for the construction of a continuous beam bridge across a railway using the rotation method, as described in claim 1 or 5, is characterized in that... The weighing system (3) includes: Lifting jacks (31) are installed on the upper end of the weighing support system (4) via steel beams. A dial indicator (32) is located inside the lifting jack (31), and the measuring rod of the dial indicator (32) is pressed against the bottom of the concrete box girder (11); The weighing system (3) also includes a data acquisition unit (33), a pressure sensor, a displacement sensor and a PLC control console (36). The displacement sensor and the data acquisition unit (33) are connected by a data cable, as are the pressure sensor and the data acquisition unit (33). The data acquisition unit (33), the pressure sensor, and the displacement sensor are all connected to the PLC control console (36) by a data cable.

7. A small-jacking-force-supported structure for the construction of a continuous beam bridge across a railway using the rotation method, as described in claim 1, is characterized in that... The concrete box girder (11) is equipped with a counterweight system (5) on its upper part. The counterweight system (5) is a counterweight water tank (51), and the counterweight water tank (51) is connected by steel profile connectors.

8. A small-load-bearing structure for the construction of a continuous beam bridge across a railway using the rotation method, as described in claim 5, is characterized in that... The load-bearing support system (4) is located 0.7m from the end of the concrete box girder (11).

9. A small-force weighing method for the construction of a continuous beam bridge across a railway using the rotation method, characterized in that, This method is based on the small jacking force weighing structure for the construction of a continuous beam bridge across a railway as described in any one of claims 1 to 8.

10. A method for weighing under small jacking forces during the rotation construction of a continuous beam bridge across a railway, as described in claim 9, is characterized in that... The weighing structure is used to test rigid body displacement abrupt changes, and the weighing is divided into the following forms: The first form is: When the frictional torque M provided by the rotating ball joint (16) Z Greater than the unbalanced torque M of the rotating body itself G At this time, the unbalanced torque of the rotating body is canceled out by the frictional torque generated by the ball joint, and the beam maintains a balanced state and will not produce rigid body displacement around the ball joint (16). At this time, the support foot is not on the ground, and the jacking force is applied on both sides of the rotating body in the longitudinal or transverse direction respectively; during the jacking process, the rotating body undergoes small counterclockwise and clockwise rotations in the vertical plane along the beam axis. By drawing the jacking force-displacement curve, the critical point and critical jacking forces P1 and P2 are found. A system of simultaneous equations is established based on the torque balance principle to solve for the frictional torque M of the ball joint of the rotating body. Z and the unbalanced torque M of the rotating body itself G ; M G =(P1L1-P2L2) / 2; M Z =(P1L1+P2L2) / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P2: Lifting force at the critical state of slight rotation at the second end of the concrete box girder; L1: Lever arm of the lifting force at the first end of the concrete box girder; L2: Lever arm of the lifting force at the second end of the concrete box girder; The second form is: When the frictional torque M provided by the rotating ball joint (16) Z Less than the unbalanced torque M of the rotating body itself G At this time, the frictional resistance generated by the rotating ball joint (16) is insufficient to resist the unbalanced moment of the rotating body itself. After the beam undergoes rigid body displacement, the support legs participate in the work. The resistance torque generated by the support legs and the frictional resistance torque of the rotating ball joint (16) jointly resist the unbalanced moment of the rotating body and maintain the stability of the system. At this time, the support legs touch the ground and the top force is applied on the side where the support legs touch the ground. Record the jacking force, starting from the moment the support foot leaves the ground, gradually increasing to the moment when the ball joint rotates slightly, P1. Then lower the jack, and let P1' be the jacking force at the moment the ball joint rotates slightly during the gradual lowering process. During the lifting and lowering process, by plotting the jacking force-displacement curve, find the critical point and the critical lifting forces P1 and P1'. Establish a system of simultaneous equations based on the torque balance principle to solve for the frictional torque M of the rotating ball joint. Z and the unbalanced torque M of the rotating body itself G ; M G =(P1+P1')L1 / 2; M Z =(P1-P1')L1 / 2; In the above formula: P1: Lifting force at the critical state of slight rotation at the first end of the concrete box girder; P1': Lifting force at the critical state of slight rotation during the fall of the first end of the concrete box girder; L1: The lever arm of the lifting force at the first end of the concrete box girder.

11. The method for small-force weighing during the rotation construction of a continuous beam bridge across a railway, as described in claim 10, is characterized in that... The eccentricities of the two types of rotating bodies are: e=M G / G; The static friction coefficient of the rotating ball joint is: µ =M Z / (RG); In the formula: M G —The unbalanced torque of the rotating body itself; M Z —Spherical hinge friction torque; R—radius of the ball joint; G—Total weight of the rotating body.

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